added greetd greeter for niri

modules/system/display-managers/greetd.nix

@@ -0,0 +1,35 @@
+{ lib, config, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.settings.display-manager;
+in {
+  config = mkIf (cfg == "greetd") {
+    # systemd.services.greetd = {
+    #   serviceConfig.Type = "idle";
+    #   # unitConfig.After = [ "docker.service" ];
+    # };
+
+    systemd.services.greetd.serviceConfig = {
+      Type = "idle";
+      StandardInput = "tty";
+      StandardOutput = "tty";
+      StandardError = "journal"; # Without this errors will spam on screen
+      # Without these bootlogs will spam on screen
+      TTYReset = true;
+      TTYVHangup = true;
+      TTYVTDisallocate = true;
+    };
+
+    services.greetd = {
+      enable = true;
+      settings = {
+        default_session = {
+          command = "${pkgs.greetd.tuigreet}/bin/tuigreet --time --cmd niri-session";
+          user = "greeter";
+        };
+      };
+    };
+  };
+}